JP7478726B2 - CONTROL METHOD, DATA GENERATION DEVICE, AND PROGRAM - Google Patents

Description

The present disclosure relates to a control method, a data generation device, and a program.

Blockchain technology is a technology that was born from Bitcoin (see, for example, Non-Patent Document 1). Blockchain is a database that stores data by generating units of data called blocks at regular intervals and linking them like a chain. By using blockchain, transaction history (transaction data) can be shared and mutually monitored in a peer-to-peer (P2P) network in which anyone can participate, ensuring reliability and preventing data tampering.

In addition, in the Bitcoin blockchain described in Non-Patent Document 1, the block size is limited to 1 MB, and the block generation interval is approximately 10 minutes.

For this reason, the specifications of the blockchain have been changed to increase the block generation interval to about two minutes, thereby increasing the amount of data processed (see, for example, Non-Patent Document 2).

Satoshi Nakamoto, “Bitcoin: A Peer-to-Peer Electronic Cash System”, 2009 BitcoinCandy, “Bitcoin Candy Whitepaper”, (https://cdy.one/whitepaper.pdf)

In the blockchains described in Non-Patent Document 1 and Non-Patent Document 2, multiple transaction data are generated in one block. Therefore, depending on the block generation interval, multiple transaction data sent by the same user or the same business at multiple points in time may be included in one block.

However, depending on the type of information included in the transaction data, it may be meaningless for one block to contain multiple transaction data sent by the same user or the same business at multiple points in time. One example would be when determining prices based only on the latest weather information recorded in the blockchain, in which case non-latest weather information is also included in one block. In other words, only the transaction data containing the latest information among the multiple transaction data contained in a block is used, and transaction data containing older information is not used. In such cases, unused and unnecessary transaction data will be recorded in the blockchain blocks. This not only wastes limited network bandwidth, but also wastes resources including the electricity used to generate blocks.

This disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a control method, etc. that can reduce waste of network bandwidth and resources.

In order to achieve the above-mentioned object, the control method disclosed herein is a control method executed by an apparatus in a system including a plurality of servers, each of which is communicatively connected to the apparatus and which records selected transaction data from among the transaction data held up to a predetermined time in a block in a distributed ledger at each predetermined time, the control method generating first transaction data including the latest information acquired up to a first time and transmitting the first transaction data to a first server among the plurality of servers, and at one or more second times after the first time, checking the contents of the block recorded in the distributed ledger of the first server, thereby checking whether or not a first block included when the first transaction data is recorded in the distributed ledger differs from a second block included when the second transaction data is recorded in the distributed ledger when second transaction data one transaction after the first transaction data is generated at the second time, and if the first block and the second block are different, generating the second transaction data including the latest information acquired after the first time at or after the second time and transmitting the second transaction data to the first server.

These comprehensive or specific aspects may be realized by a system, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized by any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

The control method disclosed herein can reduce waste of network bandwidth and resources.

FIG. 1 is an explanatory diagram illustrating the concept of blockchain. FIG. 2 is an explanatory diagram showing the data structure of the block chain shown in FIG. 1. FIG. 3 is an explanatory diagram of the processing performed at the block generation interval of the blockchain shown in FIG. 1. FIG. 4 is an example of a flowchart showing a process performed by executing the consensus algorithm shown in FIG. FIG. 5 is a diagram illustrating a schematic configuration of a control system according to an embodiment. FIG. 6 is a block diagram showing a schematic configuration of a device according to an embodiment. FIG. 7 is a diagram showing an example of a hardware configuration of a computer that realizes the functions of the device according to the embodiment by software. FIG. 8 is a block diagram illustrating a functional configuration of the authentication server device according to the embodiment. FIG. 9 is a flowchart showing the operation of the device according to the embodiment. FIG. 10 is a sequence diagram of the process of the control system according to the first embodiment. FIG. 11 is a flowchart illustrating processing of the device according to the second embodiment. FIG. 12 is a flow diagram for explaining the effects of the embodiment. FIG. 13 is a flow diagram for explaining the effects of the embodiment. FIG. 14 is an explanatory diagram showing the flow chart shown in FIG. 13 from another perspective.

(Findings that form the basis of this disclosure)
First, let me explain about blockchain.

Figure 1 is an explanatory diagram showing the concept of blockchain.

A blockchain is a system in which blocks are linked together in a chain, with each block being the unit of record, and these blocks are recorded in a distributed ledger. Figure 1 shows an example in which block B1, which was generated chronologically after block B0, is connected to block B0, block B2, which was generated chronologically after block B1, is connected to block B1, and so on. In other words, Figure 1 shows an example of a blockchain in which blocks B0 to B3 are connected in a chain.

Figure 2 is an explanatory diagram showing the data structure of the blockchain shown in Figure 1.

The blockchain block shown in Figure 1 contains multiple transaction data and the hash value of the immediately preceding block. Specifically, block B2 contains the hash value of the previous block B1. The hash value calculated from the multiple transaction data contained in block B2 and the hash value of block B1 is included in block B3 as the hash value of block B2.

In this way, blockchain technology effectively prevents tampering with connected transaction data by connecting blocks in a chain while including the contents of the previous block as a hash value. This is because if past transaction data is changed, the hash value of the block will be different from the value before the change. In order to make a tampered block appear correct, all subsequent blocks must be recreated, which is very difficult in reality, so it can be said that tampering is virtually impossible. Furthermore, since the distributed ledger in which the blockchain is recorded is installed at each of many physically different locations, even if tampering occurs with the ledger at one location, the tampering can be detected from the other ledgers. This also means that blockchain can be said to be virtually impossible to tamper with.

Next, the process during a block generation interval, that is, the process from when a block is generated to when it is connected (written) to the blockchain, is explained using diagrams. Note that the process from when a block is generated to when it is written to the blockchain corresponds to the process from when a blockchain block is generated to when it is recorded in the distributed ledger.

Figure 3 is an explanatory diagram of the processing performed at the block generation interval of the blockchain shown in Figure 1. In Figure 3, transaction data is represented as Tx data, and the transaction pool is represented as Tx pool. In Figure 3, the block generation interval is, for example, the interval from when block B1 is connected to block B0 of the blockchain until the next block B2 is connected.

A transaction pool is a repository that stores unverified transactions (transaction data) on the blockchain. As shown in Figure 3, the transaction pool holds multiple unverified transaction data obtained from one or more users.

A consensus algorithm is a set of rules for selecting "representatives" who can write blocks to the blockchain, and is also known as a consensus algorithm. Since it takes time to execute a consensus algorithm, the block generation interval is defined as the time from the start of execution of the consensus algorithm to its completion.

The consensus algorithm is executed on one or more transaction data selected in the transaction pool by the time execution begins. When execution of the consensus algorithm is completed, the block is written to the blockchain. Note that if there is block capacity that can contain all of the transaction data held in the transaction pool, the consensus algorithm may be executed on all of the transaction data held in the transaction pool.

Figure 4 is an example flowchart showing the processing performed by executing the consensus algorithm shown in Figure 3.

When the consensus algorithm is executed, first, one or more transaction data selected from the transaction pool is verified (S91). Here, the validity of the one or more transaction data is verified.

Next, a block including the one or more transaction data is generated (S92) and written to the blockchain (S93). Note that, hereinafter, writing a new block to the blockchain may be expressed as recording a new block in the distributed ledger.

In this way, the block generation interval is determined by the time required to execute the consensus algorithm. In Bitcoin disclosed in Non-Patent Document 1, the block generation interval is set to about 10 minutes because it takes about 10 minutes to execute the consensus algorithm.

In addition, in such a blockchain, selected transaction data is written in a transaction pool that holds transaction data sent to be written to the blockchain.

However, in such blockchains, depending on the block generation interval, multiple transaction data sent by the same user or the same business at multiple points in time may be held in the transaction pool. In other words, multiple transaction data sent by the same user or the same business at multiple points in time may be included in one block.

However, depending on the type of information contained in the transaction data, it may be meaningless for one block to contain multiple transaction data sent at multiple times by the same user or business. In such cases, unnecessary transaction data that will not be used will be recorded in the blockchain block. This not only wastes limited network bandwidth, but also resources including the electricity used to generate blocks.

In accordance with one embodiment of the present disclosure, a control method is a control method executed by a device in a system including a device and a plurality of servers each connected to the device so as to be able to communicate with the device, and configured to record selected transaction data from among the transaction data held up to a predetermined timing in a block in a distributed ledger at each predetermined timing, the control method comprising: generating first transaction data including the latest information acquired up to a first time, transmitting the first transaction data to a first server among the plurality of servers; and at one or more second times after the first time, checking the contents of the block recorded in the distributed ledger of the first server, thereby checking whether or not a first block included when the first transaction data is recorded in the distributed ledger differs from a second block included when the second transaction data is recorded in the distributed ledger when second transaction data one transaction after the first transaction data is generated at the second time; and if the first block and the second block are different, generating the second transaction data including the latest information acquired after the first time at or after the second time, and transmitting the second transaction data to the first server.

In this way, after checking the contents of the block recorded in the distributed ledger, one device, i.e. the same user or the same business, sends one transaction data containing the latest information. As a result, one block recorded in the distributed ledger contains only one transaction data sent by one device. This prevents unused and unnecessary transaction data from being recorded in a block, thereby reducing waste of network bandwidth and resources.

In addition, when checking the contents of the block, it may be possible to check whether the block contains a third transaction data that was generated immediately before the first transaction data.

As a result, each block recorded in the distributed ledger contains only one transaction data sent by one device. This not only prevents unused transaction data from being recorded in the distributed ledger, but also prevents blank blocks for that device from being recorded in the distributed ledger. This further reduces waste of network bandwidth and resources.

Here, the first server may further obtain a total number of received transactions, which is the number of transaction data received per unit time, and a processable number, which is the number of transaction data that the first server can process per unit time when recording in the distributed ledger, and if the processable number is equal to or greater than a threshold determined by the total number of received transactions, it may be possible to confirm whether the block contains the third transaction data as the contents of the block.

This allows each block recorded in the distributed ledger to contain only one transaction data sent by one device, depending on the processing power of the first server.

In addition, when checking the contents of the block, it may be possible to check whether the block contains the first transaction data.

As a result, although there may be cases where a blank block for that one device is recorded in the distributed ledger, a single non-blank block recorded in the distributed ledger will contain only one transaction data sent by one device. This prevents unused and unnecessary transaction data from being recorded in a block, thereby reducing waste of network bandwidth and resources.

Here, the first server may further obtain a total number of received transactions, which is the number of transaction data received per unit time, and a processable number, which is the number of transaction data that the first server can process per unit time when recording in the distributed ledger, and if the processable number is smaller than a threshold value determined by the total number of received transactions, it may be possible to confirm whether the block contains the first transaction data as the contents of the block.

This allows one block recorded in the distributed ledger to contain only one transaction data sent by one device, depending on the processing capacity of the first server.

In addition, a data generation device according to one aspect of the present disclosure is a data generation device communicatively connected to a plurality of servers, each of which includes selected transaction data from among transaction data held up to a predetermined timing in a block and records the transaction data in a distributed ledger for each predetermined timing, and includes a processor and a memory, wherein the processor generates first transaction data including the latest information acquired up to a first time and transmits the first transaction data to a first server among the plurality of servers, and the processor checks the contents of the blocks recorded in the distributed ledger of the first server at one or more second times after the first time, thereby checking whether or not a first block included when the first transaction data is recorded in the distributed ledger differs from a second block included when the second transaction data is recorded in the distributed ledger when second transaction data one transaction after the first transaction data is generated at the second time, and if the processor checks that the first block and the second block are different, generates the second transaction data including the latest information acquired after the first time at or after the second time and transmits the second transaction data to the first server.

The following describes the embodiments with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present disclosure. In other words, the numerical values, shapes, materials, components, arrangement and connection of the components, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. The present disclosure is specified based on the claims. Therefore, among the components in the following embodiments, components that are not described in the independent claims that show the highest concept of the present disclosure are described as components that are not necessarily required to achieve the objectives of the present disclosure but that constitute a more preferred form.

(Embodiment)
A control system according to an embodiment will be described below with reference to the drawings.

In the control system disclosed herein, the next transaction data is transmitted depending on the results of checking the contents of the block recorded in the latest distributed ledger. As a result, if you want to record information in the distributed ledger periodically, but want to use only the latest information without referencing past information recorded in the distributed ledger, one block recorded in the distributed ledger will contain only one transaction data item that contains the latest information that can be used.

[Control system configuration]
FIG. 5 is a diagram showing a schematic configuration of a control system according to the present embodiment.

As shown in FIG. 5, the control system includes a device 100 and authentication server devices 210, 220, and 230. These are connected to each other so that they can communicate with each other. The communication between these devices may be via a wired Internet line, wireless communication, dedicated communication, or the like.

Note that, although FIG. 5 shows an example in which the control system according to this embodiment includes three servers and one device, this is not limited to this. That is, the control system according to this embodiment may include four or more authentication server devices, or may include two or more devices. Note that, as will be described later, one device may represent devices used by one user or one business operator, and may be a device with server functionality.

[Device 100]
The device 100 represents a device used by one user or one business entity, and may have a server function.

Figure 6 is a block diagram showing a schematic configuration of device 100 in this embodiment.

The device 100 comprises a processor and a memory in which a program for causing the processor to execute a predetermined process is stored. In other words, the device 100 is realized by the processor executing the predetermined program using the memory. In this embodiment, the device 100 comprises a sensor information acquisition unit 101, a transaction data generation unit 102, a transaction data confirmation unit 103, a confirmation method determination unit 104, and a communication unit 105. Note that the confirmation method determination unit 104 is not a required component and may not be included in the device 100. Each component will be described below.

<Sensor information acquisition unit 101>
The sensor information acquisition unit 101 periodically acquires information (sensor information) from a sensor mounted on an IoT (Internet of Things) device (not shown). That is, the sensor information acquisition unit 101 periodically acquires the latest sensor information (hereinafter also referred to as the latest information). Here, the sensor information is, for example, weather information or biological information, but is not limited to these. The sensor information may be data acquired directly from the sensor, or may be data acquired from the sensor via, for example, the Internet. The sensor information may also be data acquired from the Internet that is periodically updated or added.

<Transaction Data Generation Unit 102>
The transaction data generation unit 102 generates transaction data based on the confirmation result of the transaction data confirmation unit 103. The transaction data generation unit 102 transmits the generated transaction data via the communication unit 105 to at least one of the authentication servers 210, 220, 230.

More specifically, the transaction data generation unit 102 generates first transaction data including the latest information acquired by the sensor information acquisition unit 101 up to the first time, and transmits the generated first transaction data to, for example, the authentication server device 210. In this case, the transaction data generation unit 102 generates second transaction data including the latest information acquired after the first time, according to the contents of the block recorded in the latest distributed ledger by the transaction data confirmation unit 103. Then, the transaction data generation unit 102 transmits the generated second transaction data to the authentication server device 210.

<Transaction Data Verification Unit 103>
The transaction data confirmation unit 103 checks whether the block recorded in the latest distributed ledger contains the transaction data generated and transmitted one or two blocks ago by the transaction data generation unit 102. By checking the contents of the block recorded in the latest distributed ledger, it is possible to check whether the timing has come for the transaction data to be generated next by the transaction data generation unit 102 to be recorded in a different block from the previously generated transaction data.

More specifically, the transaction data verification unit 103 verifies whether the first block and the second block are different by checking the contents of the block recorded in the distributed ledger at one or more second times after the first time.

Here, the block included when the first transaction data is recorded in the distributed ledger is referred to as the first block. When the second transaction data, which is one transaction data after the first transaction data, is generated at a second time, the block included when the second transaction data is recorded in the distributed ledger is referred to as the second block.

If the transaction data verification unit 103 confirms that the first block and the second block are different, it causes the transaction data generation unit 102 to generate, after the second time, second transaction data including the latest information obtained after the first time.

Here, the transaction data verification unit 103 may verify, for example, whether the block recorded in the latest distributed ledger contains the third transaction data generated immediately before the first transaction data. Then, when the transaction data verification unit 103 verifies that the block contains the third transaction data, it may cause the transaction data generation unit 102 to generate the second transaction data. As a result, each block recorded in the distributed ledger contains only one piece of second transaction data generated by the device 100.

Furthermore, the transaction data confirmation unit 103 may confirm, for example, whether the first transaction data is included in the block recorded in the latest distributed ledger as the content of the block. Then, when the transaction data confirmation unit 103 confirms that the first transaction data is included in the block, it may cause the transaction data generation unit 102 to generate the second transaction data. As a result, although there may be cases where a blank block that does not include the second transaction data is recorded in the distributed ledger, the one block that is not a blank block recorded in the distributed ledger will include only one piece of second transaction data generated by the device 100.

<Confirmation Method Determination Unit 104>
The confirmation method determination unit 104 may determine the method for confirming the contents of the blocks recorded in the latest distributed ledger performed by the transaction data confirmation unit 103, depending on the processing capacity of the authentication server device 210.

More specifically, the confirmation method determination unit 104 obtains the total number of received transactions, which is the number of transaction data received by the first server per unit time, and the processable number, which is the number of transaction data that the first server can process per unit time when recording in the distributed ledger.

When the processable number is equal to or greater than a threshold determined by the total number of received data, the confirmation method determination unit 104 may cause the transaction data confirmation unit 103 to confirm whether the block contains the third transaction data as the contents of the block recorded in the latest distributed ledger.

In addition, when the processable number is smaller than a threshold determined by the total number of receptions, the confirmation method determination unit 104 may cause the transaction data confirmation unit 103 to confirm whether the block contains the first transaction data as the contents of the block recorded in the latest distributed ledger.

This enables the confirmation method determination unit 104 to have the transaction data confirmation unit 103 confirm whether the block recorded in the latest distributed ledger contains the transaction data generated and transmitted by the transaction data generation unit 102 one or two blocks earlier.

The number of transaction data transmitted from multiple devices including device 100 can be obtained by checking with the authentication server device 210, etc., and even if it is not an exact number, it is possible to obtain a rough estimate sufficient to make the above confirmation. Also, the number of transaction data that can be processed per unit time is predetermined for each authentication server device 210, etc.

<Communication unit 105>
The communication unit 105 communicates with the authentication servers 210 , 220 , and 230 .

In this embodiment, the communication unit 105 transmits the transaction data generated by the transaction data generation unit 102 to at least one of the authentication server devices 210, 220, and 230. The communication unit 105 may also obtain the total number of receptions and the number that can be processed as the processing capabilities of the authentication server devices 210, 220, and 230, and transmit them to the confirmation method determination unit 104. The communication unit 105 may also obtain the latest contents of the distributed ledgers of the authentication server devices 210, 220, and 230, and transmit them to the transaction data confirmation unit 103.

[Hardware configuration of device 100]
Next, the hardware configuration of the device 100 according to the present embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of the hardware configuration of a computer 1000 that realizes the functions of the device 100 according to the present embodiment by software.

7, the computer 1000 is a computer equipped with an input device 1001, an output device 1002, a CPU 1003, an internal storage 1004, a RAM 1005, a reading device 1007, a transmission/reception device 1008, and a bus 1009. The input device 1001, the output device 1002, the CPU 1003, the internal storage 1004, the RAM 1005, the reading device 1007, and the transmission/reception device 1008 are connected by the bus 1009.

The input device 1001 is a user interface device such as an input button, a touch pad, a touch panel display, etc., and accepts user operations. The input device 1001 may be configured to accept voice operations and remote operations using a remote control or the like in addition to accepting touch operations by the user.

The internal storage 1004 is a flash memory or the like. The internal storage 1004 may also store in advance at least one of a program for implementing the functions of the device 100 and an application that utilizes the functional configuration of the device 100.

RAM 1005 is a random access memory and is used to store data, etc. when executing a program or application.

The reading device 1007 reads information from a recording medium such as a USB (Universal Serial Bus) memory. The reading device 1007 reads the above-mentioned programs and applications from a recording medium on which the programs and applications are recorded, and stores the programs and applications in the built-in storage 1004.

The transmitting/receiving device 1008 is a communication circuit for performing wireless or wired communication. The transmitting/receiving device 1008 communicates with, for example, a server device connected to a network, downloads the above-mentioned programs and applications from the server device, and stores them in the built-in storage 1004.

The CPU 1003 is a central processing unit that copies programs and applications stored in the internal storage 1004 to the RAM 1005, and sequentially reads and executes instructions contained in the programs or applications from the RAM 1005.

Next, we will explain the authentication server device 210.

[Authentication server device 210]
Since the authentication servers 210, 220, and 230 have the same configuration, the authentication server 210 will be described as an example.

Figure 8 is a block diagram showing the functional configuration of the authentication server device 210 in this embodiment.

The authentication server device 210 is communicatively connected to the device 100, and at each predetermined timing, selects transaction data from the transaction data held up to the predetermined timing and records the selected transaction data in a block in the distributed ledger. The authentication server device 210 is an example of a first server that records in the distributed ledger.

In this embodiment, as shown in FIG. 8, the authentication server device 210 includes a transaction data storage unit 211, a transaction data verification unit 212, a ledger storage unit 213, and a communication unit 214. The authentication server device 210 can be realized by a processor using a memory to execute a predetermined program. Each component will be described below.

<Transaction Data Storage Unit 211>
The transaction data storage unit 211 functions as a transaction pool that stores transaction data that has not yet been verified in the blockchain.

In this embodiment, the transaction data storage unit 211 stores and temporarily retains, for example, the first transaction data, the second transaction data, or the third transaction data acquired from the device 100. The transaction data storage unit 211 deletes transaction data that has been selected from the transaction data it retains and written to the distributed ledger, and discards transaction data that is no longer necessary.

When the transaction data storage unit 211 acquires transaction data from the device 100, the transaction data storage unit 211 may verify the electronic signature included in the transaction data and verify the validity of the transaction data. The transaction data storage unit 211 may retain the transaction data acquired from the device 100 only when the verification of the transaction data acquired from the device 100 is successful. This verification may be skipped.

<Transaction Data Verification Unit 212>
The transaction data verification unit 212 executes a consensus algorithm to verify the validity of transaction data selected from the transaction data stored in the transaction data storage unit 211.

Here, the consensus algorithm may be PBFT (Practical Byzantine Fault Tolerance) or other known consensus algorithms. Examples of known consensus algorithms include POW (Proof Of Work) and POS (Proof Of Stake). When PBFT is used as the consensus algorithm, the transaction data verification unit 212 receives reports indicating whether or not the verification of the transaction data has been successful from each of the other multiple authentication server devices 220 and 230, and determines whether or not the number of such reports exceeds a predetermined number. Then, when the number of such reports exceeds the predetermined number, the transaction data verification unit 212 may determine that the validity of the transaction data has been verified by the consensus algorithm.

<Ledger Storage Unit 213>
The ledger storage unit 213 is a processing unit that stores new transaction data to be stored in the distributed ledger in the distributed ledger.

In this embodiment, the ledger storage unit 213 generates a block including transaction data whose validity has been verified by the transaction data verification unit 212, and stores the generated block in the distributed ledger. In other words, the ledger storage unit 213 generates a block including transaction data whose validity has been verified by the transaction data verification unit 212, and writes the block to the blockchain stored in the distributed ledger.

<Communication unit 214>
The communication unit 214 communicates with the authentication server devices 220 and 230 and with the device 100 .

In this embodiment, the communication unit 214 transmits the transaction data to be verified by the transaction data verification unit 212 to the authentication server devices 220 and 230. The communication unit 214 may also communicate with the device 100 to acquire transaction data, and may transmit to the device 100 the total number of received transactions and the number that can be processed as the processing capacity of the authentication server device 210 itself. The communication unit 214 may also transmit to the device 100 the contents of the distributed ledger that the authentication server device 210 itself owns.

[motion]
Next, the operation of the device 100 included in the control system configured as above will be described.

Figure 9 is a flowchart showing the operation of device 100 in this embodiment.

Figure 9 shows an operation for device 100 to ensure that only one transaction data sent by device 100 is included among one or more transaction data contained in one block recorded in the distributed ledger.

First, the device 100 generates first transaction data including the latest information acquired up to the first time and transmits the first transaction data to the first server (S10). As described above, the first server corresponds to, for example, the authentication server device 210.

Next, the device 100 checks the contents of the block recorded in the distributed ledger of the first server at a second time after the first time (S11). More specifically, the device 100 checks the contents of the block recorded in the distributed ledger, and checks whether the second transaction data, which is one transaction data after the first transaction data, is included in a block different from the first transaction data when the second transaction data is generated at the second time.

Next, when the second transaction data is generated at the second time and is included in a different block from the first transaction data (YES in S12), the device 100 generates second transaction data including the latest information acquired after the first time and transmits it to the first server (S13). In this embodiment, the device 100 generates the second transaction data from after the second time until the execution of the consensus algorithm being executed at the second time is completed, and transmits it to the first server.

In addition, when the device 100 generates the second transaction data at the second time, if the second transaction data is included in the same block as the first transaction data (No in S12), the device 100 returns to step S11 and repeats the process.

Example 1
Next, as Example 1, we will explain the processing of the control system when device 100 checks whether the block contents recorded in the latest distributed ledger include the transaction data sent by device 100 itself two blocks ago.

Figure 10 is a sequence diagram of the processing of the control system according to Example 1. Figure 10 shows an example of the processing of the control system from S11 onwards shown in Figure 9.

Here, the device 100 generates first transaction data including the latest information acquired up to the first time and transmits it to the authentication server devices 210, 220, and 230, and the first transaction data is at least pooled (stored) in the authentication server devices 210, 220, and 230.

Next, at a second time after the first time, the device 100 checks the latest distributed ledger of the authentication server device 210 (S21). In this embodiment, the device 100 checks the latest distributed ledger by, for example, requesting the latest distributed ledger from the authentication server device 210 and acquiring the latest distributed ledger sent by the authentication server device 210.

Next, device 100 refers to (checks) the latest distributed ledger block acquired and checks whether it contains the third transaction data sent by device 100 itself two transactions ago (S22). Here, the transaction data sent by device 100 one transaction ago is regarded as the first transaction data. Also, the transaction data sent by device 100 two transactions ago, i.e., one transaction before the first transaction data, is regarded as the third transaction data. In other words, the transaction data sent one transaction ago is referred to as the first transaction data based on the second transaction data that device 100 will generate and send from now (i.e., after the second time). Also, the transaction data sent two transactions ago is referred to as the third transaction data based on the second transaction data that device 100 will send from now.

In step S22, if the third transaction data transmitted by the device 100 itself two transactions ago is included in the latest distributed ledger (YES in S22), the device 100 generates second transaction data including the latest information acquired after the first time (S23). Note that in step S22, if the third transaction data transmitted by the device 100 itself two transactions ago is not included in the latest distributed ledger (NO in S22), the device 100 returns to step S21 and repeats the process.

Next, the device 100 transmits the second transaction data generated in step S23 to the authentication server devices 210, 220, and 230 (S24).

Then, the authentication server devices 210, 220, and 230 each pool (store) the second transaction data obtained from the equipment 100 (S25).

Example 2
Next, a process in which the device 100 determines a method for checking the contents of a block recorded in the latest distributed ledger of the authentication server device 210 according to the processing capacity of the authentication server device 210 will be described as Example 2. In addition, in this example, the method for checking the contents of a block will be described as a method for checking whether or not the transaction data transmitted by the device 100 itself two blocks prior or one block prior is included in the block recorded in the latest distributed ledger.

Figure 11 is a flowchart showing the processing of device 100 relating to Example 2.

Before performing step S31 described below, the device 100 generates first transaction data including the latest information acquired up to the first time and transmits it to the authentication server device 210, and the first transaction data is at least pooled (stored) in the authentication server device 210.

First, the device 100 obtains from the authentication server device 210 the number of processes that can be performed per unit time and the total number of receptions at the authentication server device 210 (S31).

Next, the device 100 checks whether the processable number acquired in step S31 is equal to or greater than a threshold (i.e., processable number ≧ threshold) (S32). The threshold here is determined from the total number of receptions acquired by the device 100 in step S31, and is set to a value of, for example, several percent to several tens of percent of the total number of receptions.

In step S32, if the processable number is smaller than the threshold value (NO in S32), at the second time after the first time, the device 100 checks the latest distributed ledger of the authentication server device 210 (S33). In this embodiment, the device 100 also checks the latest distributed ledger by, for example, requesting the latest distributed ledger from the authentication server device 210 and acquiring the latest distributed ledger sent by the authentication server device 210.

On the other hand, in step S32, if the number of processes that can be performed is equal to or greater than the threshold value (YES in S32), the process proceeds to step S33. The subsequent processes, i.e., steps S33, S35, and S36, are the same as those described in steps S21 to S24 of FIG. 10, and therefore will not be described here.

Although the device 100 has been described as generating first transaction data including the latest information and transmitting it to the authentication server device 210 before step S31, this is not limited to the above. After steps S31 and S32 and before step S33, the device 100 may generate first transaction data including the latest information and transmit it to the authentication server device 210.

[Effects, etc.]
As described above, according to the control system etc. of the embodiment, after checking the contents of the block recorded in the distributed ledger, one device 100, i.e., the same user or the same business, transmits one transaction data including the latest information. In other words, in the control system etc. of the embodiment, the device 100 does not transmit the transaction data in the PUSH type, but transmits the transaction data one by one in the ASK type. As a result, one block recorded in the distributed ledger contains only one transaction data transmitted by one device 100 for the device 100. Therefore, it is possible to prevent unnecessary transaction data that is not used from being recorded in a block, and therefore it is possible to prevent waste of network bandwidth and resources.

Here, the effects of the embodiment will be described with reference to Figures 12 to 14. Figures 12 and 13 are flow diagrams for explaining the effects of the embodiment. Figure 14 is an explanatory diagram from a different perspective of the flow diagram shown in Figure 13.

First, using FIG. 12, we will explain the case where device 100 generates and transmits second transaction data after confirming that the first transaction data generated immediately before is included in the block recorded in the latest distributed ledger, based on the second transaction data to be generated next.

In FIG. 12, the first transaction data is denoted as Tx _n-1 , and the second transaction data is denoted as Tx _n . The period during which the consensus algorithm is executed is denoted as consensus. The period during which the consensus algorithm is executed is shown as the period required to write a block to the blockchain. In the blockchain shown in FIG. 12, the consensus algorithm is executed on the transaction data transmitted before the start of the consensus algorithm, and after the execution of the consensus algorithm is completed, the transaction data is included in a block and written to the blockchain. The transaction data transmitted before the start of the consensus algorithm is held in a transaction pool.

As shown in Fig. 12, the device 100 may periodically check whether Tx _n-1 , which was generated and transmitted, is included in a block written to the blockchain. In this case, when the device 100 confirms that Tx _n-1 is included in a block written to the blockchain, it generates and transmits Tx _n . Then, each of the successive blocks does not contain the transaction data generated and transmitted by the device 100 (a blank block occurs for the device 100). However, a block that is not a blank block contains only one transaction data generated and transmitted by the device 100 for the device 100.

In other words, the device 100 may transmit the next transaction data after confirming that the block written to the blockchain contains the transaction data previously transmitted by the device 100. This prevents two or more transaction data transmitted by the device 100 from being included in one block, although a blank block for the device 100 may be generated in the block written to the blockchain.

In this way, although there may be cases where a blank block is recorded in the distributed ledger for device 100, a single block recorded in the distributed ledger will contain only one transaction data sent by device 100 for device 100.

This prevents unused and unnecessary transaction data from being recorded in blocks, thereby reducing waste of network bandwidth and resources.

Next, a case will be described with reference to Figures 13 and 14 in which the device 100 generates and transmits second transaction data after confirming that third transaction data generated two transactions ago based on the second transaction data to be generated next is included in a block recorded in the latest distributed ledger. Here, in Figures 13 and 14, the first transaction data is the transaction data generated one transaction ago based on the second transaction data to be generated next, and is represented as Tx _n-1 . Moreover, the second transaction data is represented as Tx _n , and the third transaction data generated one transaction before the first transaction data is represented as Tx _n-2 . Moreover, the transaction data to be generated one transaction after the second transaction data is represented as Tx _n+1 .

13 and 14, the device 100 checks whether Tx _n-2 is included in the block written to the blockchain after sending Tx _n-1 in order to check the generation and transmission timing of Tx _n . Then, when the device 100 checks that Tx _n-2 is included in the block written to the blockchain, it generates and sends Tx _n .

Next, in order to confirm the generation and transmission timing of Tx _n+1 , the device 100 checks whether Tx _n-1 was included in the block written to the blockchain after transmitting Tx _n . Then, when the device 100 confirms that Tx _n-1 was included in the block written to the blockchain, it generates and transmits Tx _n+1 . Therefore, each successive block contains the transaction data generated and transmitted by the device 100 (no blank blocks are generated for the device 100).

In this way, device 100 confirms that the block written to the blockchain contains the transaction data sent by device 100 two blocks ago before sending the next transaction data. As a result, one block contains only one piece of transaction data generated and sent by device 100 for device 100. In other words, it is possible to prevent two or more pieces of transaction data sent by device 100 from being included in one block. In addition, since each block contains only one piece of transaction data generated and sent by device 100 for device 100, it is also possible to prevent blank blocks from being generated for device 100.

In other words, not only can it be prevented that one or more unused transaction data are included in a block and recorded in the distributed ledger, but it can also be prevented that blank blocks for the device are recorded in the distributed ledger. This can further reduce waste of network bandwidth and resources.

In addition, depending on the processing capacity of the authentication server device having the distributed ledger, it may be confirmed that the first transaction data is included in the block recorded in the latest distributed ledger, or that the third transaction data generated immediately before the first transaction data is included. This makes it possible to select whether or not to allow a case in which a blank block for the device 100 is recorded in the distributed ledger depending on the processing capacity of the authentication server device.

[Other Modifications]
Although the present disclosure has been described based on the above-mentioned embodiments, the present disclosure is not limited to the above-mentioned embodiments. The following cases are also included in the present disclosure.

(1) Specifically, each device in the above embodiments is a computer system composed of a microprocessor, ROM, RAM, a hard disk unit, a display unit, a keyboard, a mouse, etc. A computer program is recorded in the RAM or hard disk unit. Each device achieves its function by the microprocessor operating in accordance with the computer program. Here, a computer program is composed of a combination of multiple instruction codes that indicate commands to a computer to achieve a specified function.

(2) In each of the devices according to the above embodiments, some or all of the constituent elements may be composed of a single system LSI (Large Scale Integration). A system LSI is an ultra-multifunctional LSI manufactured by integrating multiple components on a single chip, and specifically, is a computer system including a microprocessor, ROM, RAM, etc. A computer program is recorded in the RAM. The system LSI achieves its functions by the microprocessor operating in accordance with the computer program.

In addition, each part of the components constituting each of the above devices may be individually integrated into a single chip, or may be integrated into a single chip to include some or all of the components.

Although the term "system LSI" is used here, it may also be called an IC, LSI, super LSI, or ultra LSI depending on the level of integration. The integrated circuit method is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. After LSI manufacturing, a field programmable gate array (FPGA) that can be programmed, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may also be used.

Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derived technologies, it is natural that such technology can be used to integrate functional blocks. The application of biotechnology, etc. is also a possibility.

(3) Some or all of the components constituting each of the above devices may be composed of an IC card or a standalone module that can be attached to each device. The IC card or the module is a computer system composed of a microprocessor, ROM, RAM, etc. The IC card or the module may include the above-mentioned ultra-multifunction LSI. The IC card or the module achieves its functions by the microprocessor operating in accordance with a computer program. This IC card or this module may be tamper-resistant.

(4) The present disclosure may be the methods described above. It may also be a computer program for implementing these methods by a computer, or a digital signal comprising the computer program.

The present disclosure may also be the computer program or the digital signal recorded on a computer-readable recording medium, such as a flexible disk, a hard disk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, a BD (Blu-ray (registered trademark) Disc), a semiconductor memory, etc. The present disclosure may also be the digital signal recorded on such a recording medium.

The present disclosure may also involve transmitting the computer program or the digital signal via a telecommunications line, a wireless or wired communication line, a network such as the Internet, data broadcasting, etc.

The present disclosure may also provide a computer system having a microprocessor and a memory, the memory storing the above-mentioned computer program, and the microprocessor operating in accordance with the computer program.

The program or the digital signal may also be implemented by another independent computer system by recording it on the recording medium and transferring it, or by transferring the program or the digital signal via the network, etc.

(5) The above embodiments and the above variations may be combined with each other.

The present disclosure can be used in a control method and data generation device for transaction data recorded in a distributed ledger, and in particular in a control method and data generation device for transaction data recorded in a distributed ledger that periodically records the latest information in a distributed ledger but uses only the latest information and does not use past information.

REFERENCE SIGNS LIST 100 Device 101 Sensor information acquisition unit 102 Transaction data generation unit 103 Transaction data confirmation unit 104 Confirmation method determination unit 105, 214 Communication unit 210, 220, 230 Authentication server device 211 Transaction data storage unit 212 Transaction data verification unit 213 Ledger storage unit

Claims (7)

A control method executed by a device in a system including the device and a plurality of servers each communicatively connected to the device, the plurality of servers each including selected transaction data among transaction data held up to a predetermined timing in a block and recording the selected transaction data in a distributed ledger at a predetermined timing, the method comprising:
generating first transaction data including the latest information acquired up to a first time, and transmitting the first transaction data to a first server among the plurality of servers;
by checking the contents of the blocks recorded in the distributed ledger of the first server at one or more second times after the first time, when second transaction data that is one transaction after the first transaction data is generated at the second time, checking whether a first block included when the first transaction data is recorded in the distributed ledger differs from a second block included when the second transaction data is recorded in the distributed ledger;
If the first block and the second block are different, the second transaction data including the latest information acquired after the first time is generated after the second time, and transmitted to the first server.
Control methods. When checking the contents of said block,
confirming whether the block contains a third transaction data generated immediately before the first transaction data, as the content of the block;
The control method according to claim 1 . Furthermore, the first server acquires a total number of received transaction data, which is the number of transaction data received per unit time, and a processable number, which is the number of transaction data that the first server can process per unit time when recording in the distributed ledger;
if the processable number is equal to or greater than a threshold determined by the total number of received data, confirming whether the block contains the third transaction data as content of the block;
The control method according to claim 2 . When checking the contents of said block,
confirming whether the block contains the first transaction data as a content of the block;
The control method according to claim 1 . Further, the first server acquires a total number of received transaction data, which is the number of transaction data received per unit time, and a processable number, which is the number of transaction data that the first server can process per unit time when recording in the distributed ledger;
if the processable number is smaller than a threshold determined by the total number of received data, confirming whether the block contains the first transaction data as a content of the block;
5. The control method according to claim 3 or 4. a data generation device communicably connected to a plurality of servers, each of which includes selected transaction data among transaction data held up to a predetermined time in a block and records the selected transaction data in a distributed ledger at each predetermined time,
A processor;
A memory,
The processor generates first transaction data including the latest information acquired up to a first time, and transmits the first transaction data to a first server among the plurality of servers;
the processor checks the contents of the blocks recorded in the distributed ledger of the first server at one or more second times after the first time, thereby checking whether or not a first block included when the first transaction data is recorded in the distributed ledger differs from a second block included when the second transaction data is recorded in the distributed ledger when second transaction data that is one transaction after the first transaction data is generated at the second time;
When the processor confirms that the first block and the second block are different, the processor generates the second transaction data after the second time, the second transaction data including the latest information acquired after the first time, and transmits the second transaction data to the first server.
Data generation device. A program for causing a computer to execute a control method executed by a device in a system including a device and a plurality of servers each communicably connected to the device, the plurality of servers including selected transaction data from transaction data held up to a predetermined timing in a block and recording the selected transaction data in a distributed ledger at each predetermined timing, the program comprising:
generating first transaction data including the latest information acquired up to a first time, and transmitting the first transaction data to a first server among the plurality of servers;
by checking the contents of the blocks recorded in the distributed ledger of the first server at one or more second times after the first time, when second transaction data that is one transaction after the first transaction data is generated at the second time, checking whether a first block included when the first transaction data is recorded in the distributed ledger differs from a second block included when the second transaction data is recorded in the distributed ledger;
if it is determined that the first block and the second block are different, generating the second transaction data including the latest information acquired after the first time after the second time, and transmitting the second transaction data to the first server;
A program for a computer to execute.

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